1. This invention relates to an explosion-proof type electro-displacement converter and more particularly to an explosion-proof type electro-displacement converter device of a simplified structure to facilitate easy assembly and adjustment.
2. Description of the Prior Art
Conventional electro-displacement converter applicable to electropneumatic measuring instruments, such as electropneumatic converters, regulator valve electropneumatic positioners, etc. have been required to be explosion-proof even in an explosive gas environment. For this reason, a structure to enclose the whole electro-displacement converter device in an explosion-proof case has been used. However, there is an unavoidable handling disadvantage in such a structure. Since it was sometimes dangerous to detach a cover of the explosion-case for the purpose of adjustment, repairs or replacements. One prior art modification accommodates the whole drive unit (torque motor) including a core as a magnetic path and other parts including an exciter coil in a separate sealed container. In that case, one extra independent sealed container is required thereby producing an increase in the size of the equipment.